Carburetor



Oct. 5, 1937. i R, ABE-LL i 2,094,864

CARBURETOR Filed Jan. 17, 1955 any Patented oct. s, 1931" UNITED STATES PATENT OFFICE;

cAitBUBE'roR. Rllln Abell, Milton, M888.

Application January 17, 1933, ScriaFNo. 652,179 1v claims. (ci. zei-.49)

Thisinventlon relates to improvements in car- -"buretors and particularly to a carburetor of the type that has the constant vacuum or gravity air valve principle embodied therein.

5 'I'he primary object of the invention is to provide a carburetor which does not require a ioat and also does not require a fuel pump or other mechanism of any description to feed the fuel thereto, said carburetor being so constructed and arranged as to be capable of lifting its own fuel from a storage tank -at any speed or load by reason ofthe fact that the vacuum is constant irrespective of other variable conditions which may exist.

l5 Another object of the invention is to provide a carburetor having an air valve embodied therein which is capable of functioning to feed air at a constant vacuum at all loads and speeds; that is capable of feeding air at an accurate and predeterminedfrate at any position of its movement;

that functions as both a mechanical and air friction .dash pot to maintain stability of the mixture ratio under quick throttle changes and improves the acceleration of an internal combus- 25- tion engine for which it may be provided by preventing the mixture from becoming too lean on a sudden opening of said throttle, it not being necessary to resort to a throttle operated acceleration pump as is commonv on high-priced carburetors; and finally, it carries a metering pin that controls the fuel flow andv has sufficient movement so that it is not diflicult to maintain uniqform accuracy of the angle of the air valve or the taper of the metering pin. Another object of the invention is to provide a manually actuated cold weather starting device operable from the dash in the usualwell-known manner, said mechanism being of such construction that it will be impossible to choke or'flood 40 the engine to such a degree that it will not operate.

Still another object of the invention is to provide a carburetor in which it is necessary to make but vone adjustment that being for low speeds, it

being possible to so accurately control the mixture ratio through the use of1 the metering pin that no high speed adjustment is required.

Finally, it is still further the objectof the invention to provide a carburetor of small size and simple construction and capable of being manufactured at` small cost.

'I'he invention consists in a carburetor as set forth )in the following specification and, particularly as pointed out in the claims thereof.

5'5 Referring to the drawing: I

Fig. 1 represents a central vertical sectional elevation of a carburetor embodying my invention.

Fig. 2 is a detail horizontal section taken on the lirregular line 2--2 of Fig. 1. 5

Like numerals refer to like parts throughoutl l the several views of the drawing. i 15 In the drawing, 6 represents a carburetor casing embodying therein a main cylindrical portion 'I provided with a plurality of air openings 8 which extend through the wall thereof at pointsA adjacent to the lower end thereof. Formed in- 20 tegral with the body portion 'I of the casing 6 is a reduced angular portion 9 in the interior of which is amixing chamber I0 which merges into a gas fuel outlet passage II. A throttle valve I2 is provided for the outlet passage. 25

The lower extremity of the body portion 1 of the casing 6 is closed by means of a bottom member I3 which has a cyiindrical central portion or column I4 formed integral therewith. A spray nozzle I5 is rigidly secured in the bottom mem- 30 berA I3 and projects upwardly through a passage I6 which is provided in the column I4, there being a narrow space provided between theperiphery of the spray nozzle I5 and the bore oi; the

column which functions as a primary air pas- 35 sage. A liquid fuel supply pipe I1 is secured at the. lower extremityof the spray nozzle I5 by l means of a union I8. The column I4 is provided with several small air passages I9 which are positioned radially therein and incline downwardly 40 from the periphery of the column toward the Vcenter thereof and communicate with the primary air passage I6. These passages not only function as air passages but also act to collect and retain any liquid fuel which may not have 45 become vaporized and which might flow downwardly from the mixing chamber Ill vthrough the air passage I6.

passage 23 provided at the upper portion of said piston co-operates with the adjacent interior portion of the casing 6 in forming the mixing chamber I0. The lower portion of the piston 20 is internally tapered or frusto-conical at 24 and cooperates with the periphery of the'column I4 to provide a tapered passage 25 therebetween. The piston 20 has ashoulder 26 formed thereon at the point where the upstanding portion 22 joins the main body portion 2| thereof, and a space 21 is provided between this shoulder and the surface of the casing portion 1 which is located therebetween, said space surrounding the upstanding portion 22 of said piston. During the operation of the mechanism the piston 20 has a reciprocatory motion in thecasing Ii and the space 21 functions as an air cushion or air dash pot.

A piston ring 28 is mounted in the main body portion 2| of the piston 20 and acts to retard the movement of the piston.

The upper extremity of the column |4 is countersunk at 29 in order that unvaporized fuel may be deflected downwardly toward the passage I6 and not collect upon the top of said column.

Mounted in a cross arm 30 carried by .and within the tubular portion 22 of the piston 20 is a metering pin 3|, the lower portion of which is tapered at 32. The metering pin 3| has screw.- threaded engagement with the cross arm 30 and is, therefore, adjustable vertically in said arm. 'I'he metering pin 3| has an enlarged portion 33 formed thereon'which is slidably` mounted in' a bearing portion 34 of the casing 6. A spring 35 surrounds the metering pin 3| and is interposed between the cross arm 30 and the shouldered portion 33 of said pin.` 'I'he pin, furthermore, has a reduced portion 36 formed at itsupper end upon which a spring 31 is mounted. A bellcrank lever 38 is pivotally attached at 39 to an arm 4I) which is formed integral with the casing 6, and a forked portion 4| of the lever 3B straddles the upper lportion 36 of the metering pin and .is adapted to engage the upper extremity of the spring 31. An operatingrod 42 is connected to the depending arm of the bell-crank lever 38. The metering pin 33 is attened at 43 in order that it may be engaged by a suitable tool when it is necessary to make adjustments.

In Fig. 5 I have illustrated diagrammatically the preferable relationship between thecarburetor of this invention and the main-liquid fuel supply tank and an auxiliary supply tank which may be used if necessary. In this view 44 lrepresents the cylinder head of an internal combustion engine and 45 an intake manifold to which the casing 6 of the carburetor is attached in a well-known manner. I'he carburetor is connected by means of a tube 46 to an auxiliary air tight fuel supply tank 41, which is positioned at a point just below the level of the carburetor and the tank 41 is connected by means of a tube 48 to a main supply tank 49, and the tanks 41 and 49 are so positioned with relation to the carburetor that in all of the positions that an automobile may assume when being operated, as for ex` ample, in climbing very steep inclines, there will never be any extreme height to which it will be necessary for the carburetor to lift the liquid fuel.

, There will always be a reserve supply of fuel at a level near the level of the carburetor providing there is fuel inthe main supplytank.

'I'he general operation of the mechanism hereinbefore specifically described is as followsz-It is assumed that the carburetor is attached to the intake manifold of an internal combustion engine, that the fuel supply pipe I1 is attached to a fuel tank, and that the operating rod 42 extends to a location where it will be convenient for the operator as, for example, the dash of an automobile. When the engine is started, either by the starter mechanism or by cranking the engine, and a suction is created by the pistons, this suction is transmitted to the mixing chamber I0, whereupon liquid fuel will be drawn upwardly from the spray nozzle I5 through the space therein surrounding the periphery of the metering pin 3|. At the samel time air will be drawn upwardly through the primary air passage IE. 'Ihis air will mix with the fuel issuing from the spray nozzle causing the latter to be vaporized and thereby forming a gas which is drawn into the engine cylinders by means of the pistons. After the engine is started and the suction increases, the air valve or piston 20 will be influenced by the suction and start to rise, thereby moving the tapered portion of said valve abovel the upper extremity of the stationary column I4. 'I'his opens up the passage 25 between the tapered surface of the 'air valve and the outer periphery of the stationary column and causes the passage to communicate with the mixing chamber IIJ, and the higher the air valve rises the wider the space `becomes between the air valve and the column. At the same time that vthe air valve rises, the air openings 8, which at the start of the operation ofthe carburetor were substantially closed, will begin to open, thereby permitting more air to enter the carburetor and eventually reach the mixing chamber. As the air valve continues to rise, its movement will be retarded somewhat by the piston ring 28 and as the valve approaches its uppermost position air within the space 21 will act to cushion the reciprocating movements of the valve. If the throttle valve I2 is opened suddenly, there are three fac-` tors which will prevent the air valve 20 from jumping beyond its proper position. lIhe rst of these factors is the weight of the valve itself, the second is the friction caused by the presence of the piston ring 28 engaging the inner wall of the cylinder, and the third is the air cushion or dash pot.

In cold weather the manually actuated choke mechanism is utilized, at which time the bellcrank lever 38 upon being actuated will causev the forked portion 4| thereof to be depressed into engagement with the upper extremity of the spring 31, whereupon the metering pin 3| and air' valve 20 may be yieldingly held in their depressed positions in order that a rich mixture may be obtained for a longer period of time. engine finally starts to accelerate, the choke rod 42 is released, whereupon the 'air valve will start immediately to function as hereinbefore mentioned. If during the operation of the carburetor some of the liquid fuel fails to vaporize, this fuel will be deflected downwardly into the air passage I6 through which lit Will flowinto the air passages IS which are arranged in such a manner that this liquid will be trapped therein. This fuel may be utilized in a subsequent starting operation.

The device of this invention is capable of automatically providing an accurate mixture ratio at all speeds of the engine. It maintains a high vacuum at lowsypeed and a low vacuum at hig'h speed.' ABut one adjustment is necessary, that being the adjustment of the meteringlpin 3|, to vary the size of the opening of the spray nozzle When the also dserves, in this instance, as a check lvalve toy I I5. An internal combustion engine equi retor and at dierent levels with respect to each other and the carburetor, and fuel supply tubes \bonnecting the receptacles in series with said fuelwith this carburetor is capable of maintaining a very low idling speed and a relatively high top speed. A more eiiicient acceleration is obtained due to the 'inertia and friction of the air valve. No float feed is necessary and no fuel pump or other mechanism of any description is required to feed the liquid fuel to the carburetor. tion which is constant in the carburetor is transmitted through thel tube 46 to the auxiliary tank 41 and from thence through the tube 48 to the tank 49 and a supply of fuel is therefore always l available in the tank 41 near the level of the carburetor.

The auxiliary air-tight, or vacuum tank 41 is first filled to a desired level in any suitable manner and subsequent creation of a vacuum within the carburetor will draw fuel from said tank through pipe 46, which in turn will create a vacuum inthe upper portion of the tank and thev fuel level therein will vdrop slightly u'ntil all kair is'withdrawn from pipe 48 whereupon fuel from tank 49 will begin to enter vacuum tank 41 in exactly the same amount that is being drawn out through pipe 46;. hence, while the carburetor is in operation the fuel level in tank 41v remains constant. l

It will be clear that when there is no vacuum present in the carburetor, tank 49 may be raised to a level .above it and fuel 'will not flow by gravity from tank 49 to tank 41; hence, the vacuum tank prevent ooding thecarburetor when an automobile is located on a down grade with the engine stopped.

1. In a constant-vacuum floatless carburetor, the combination of a cylindrical casing having bores of different diameters, a-vacuum operated air-valve pistonrmember arranged to engage and i be guided by the wall of the larger bore, a column integral with` said piston member arranged to engage the wall of a smaller'bore to form an 'air cushioning chamber between the air-valve and ,said casing, at least one air inlet port in said,

casing, and radially expansible means positioned intermediate the air cushioning chamber and said air inlet port, wherebyithe action of said airvalve is rendered less sensitive to engine pulsations and will. respond only to vacuum changes of a predetermined degree.

2. In a constant-vacuum floatless carburetor. the combination of a casing forming a mixing chamber, ports in said casing for admitting air to said chamber, a primary air passage; a pistonvalve adapted to be lifted by suction and fitted to leave minimum openings to`said ports substancombustion engines comprising in combination,

a carburetor casing arranged to form a mixing chamber adapted for communication with an engine cylinder, a vacuum raised and gravity seated`air-controi valve lmounted within said c'asing, liquid fuel control means associated with the air-control valve, a plurality of oatless fel receptacles positioned remote from the carbumember carried by the column and extending at least to the upper end thereof in one direction and passing through the header member in the opposite direction for connection @with a source of' fuel supply; the said piston-valve-bore being in part cylindrical for the said sliding engagement with the column when the air valve is closed, and during initial openingv travel, and being in part frusto-conical, with the conical bore positioned to coact with the end of Athe column to change the area of air valve opening at arate of change greater than the linear rate of travel of the air valve.

5.- In a carburetor having a suction-operated air-and-fuel control valve, a cylindrical axial bore in said control valve arranged to merge into a frusto-conical form extending to the lower edge uof the valve, means to eng-age the lower edgeoiv the valve when in lowermost position to substantially close the frusta-conical chamber to atmospheric pressure, and a'xedlymounted cylindrical column arranged to previously close said cylindrical bore to the atmosphere, the relative closing point of each bore being controlled by valve 4dimensions predetermined. l

6. In a constant vacuum floatless carburetor,

the combination of a casing arranged to provide a mixing chamber with which an engine is adapted to communicate, Aan-`engine control valve, a fuel valve, a suction-operatedair-valve provided with a cylindrical bore, a iixedly mounted column arranged to cooperate with the bore in said air- Valve to form a secondary air passage to the mixing chamber, the positioning of said bore relative to the xed column being arranged to substantially prevent the passage of air therebetween until said air-valve has been raised a predetermined amount, and a primary air passage in the fixed column arranged to provide for communication between the mixing chamber and the atmosphere, the proportions of said primary air passage being such that said air-valve will begin to rise when the engine control valve is in engine idling position.

'7. In a self-feeding carburetor having a mixing chamber, thc combination of agravity oper- -atd air-control valve, a fuel-control element arranged to cooperate with the air-control valve to maintain a constant vacuum within the mixing chamber, a fuel supply receptacle, normally positionedat a predetermined level below the carburetor, a fuel stabilizing chamber/` positioned at an intermediate level relative, to the carburetor and said supplyr receptacle, and fuel passageways connecting the supply receptacle, the stabilizingA chamber and the carburetor in series, said stabilizing chamber being arranged to .maintain a constant level of fuel therein at all times irren spective of variations' either way from said pre- -determined level of the supply receptacle.

8. In a, self-feeding carburetor having a mixing chamber, the combination of a gravity operated air-control valve, a fuel-control element arranged to cooperate with the air-control valve to maintain a constant vacuum Within the mixing chamber, a fuel supply receptacle normally positioned at a predetermined level below the carburetor, a fuel stabilizing chamber positioned at an intermediate level relative to the carburetor and said supply receptacle, and fuel passageways connecting the supply receptacle, the stabilizing chamber and the carburetor in series, said stabilizing chamber being air-tight and arranged to provide an air lock cooperating with said passageways to prevent the flow of fuel through the chamber when said supply receptacle is raised to a level above the carburetor and there is no vacuum therein. 3

9. In a fuel feed system for an internal combustion engine, in combination, a fuel supply receptacle, a self-feeding carburetor, a vacuumoperated fuel container positioned below the carburetor, fuel conducting means leading from the Supply receptacle to the fuel container, and separate fuel conducting vacuum means leading from said container' to the carburetor.

10. In a constant vacuum carburetor, the combination of a casing arranged to provide a mixing chamber with which an engine is adapted to communicate, a throttle valve, a fuel valve having open small inlet for fuel and primary vaporizing air, a suction-operated secondary airvalve provided with a frusto-conical bore, a xedly mounted column arranged to cooperate with the bore in said air-valve to form theprincipal air passage to the] mixing chamber, the positioning of said bore relative to theoxed column being arranged sor that the air-passage area therebetween` at the smaller end of the frustum is so small in cross section that the suction will cause the air-valve to rise and functioneven when the throttle valve is in engine idling position, and the conical part of the frustum is positioned so that it 'coacts with the column, when the valve has risen, in determining the secondary air-passage area.

11. In a constant-vacuum floatless carburetor, thecombination of a casing containing a mixing chamber adapted to be connected with the intake of an internal combustion engine, a throttle valve in the outlet from said chamber, a suction operated air valve mounted in said casing with capacity for rise and descent and having a frusto-conical bore of which the sides converge inthe upward direction, a column lixedly mounted in the casing within said bore and arranged to cooperate therewith in providing a secondaryA air passage to thev mixing chamber, of which passage the area increases with .progressive rise f\said air valve, a fuel metering element carried by\said air valve and a cooperating fuel metering element arranged through said column -to coact with\\; one another in controlling delivery of fuel to the mixing chamber; said column having a primary air passage leading from the space within said conical bore and extending adjacent to said fu `l metering elements to the mixing chamber,'the primary air passage being so restricted as to cause the air valve to be substantially float- 'ed by the air column4 when -said throttle valve is in its engine-idling position. i

12. In a constant-vacuum carburetor, in combination, a casing constructed to provide. a mixing chamber in its interior, a-throttling valve controlling the outlet" fromsaid mixing chamber, a suction operated air valve having a frusto-conical bore mounted to rise and descend in said cham-` ber, a xedly mounted column in the chamber arranged to cooperate with said bore to form the principal air passage to the mixing chamber, a fuel conduit rising through said column, and a tapered fuel valve carried by the air .valve and projecting downwardly into said conduit; the respective portions of taper of the fuel valve and of taper of the conical bore which are co-acting, at each position of travel of the air valve, being related to each other in contour and dimensional proportions which make a fuel mixture in proportions which have been predetermined as being substantially the optimum for the feed of delivery to which that positioncorresponds. y

13. In a carburetor of the metering pin type, the combination .of 'a casing forming a mixing chamber and having a central upstanding column in its interior, an air valve mounted to rise and descend in said casing and having a frustoconical bore surrounding said column, having a diameter substantially equal to the diameter of the column at the upper end of the latter, and having a progressively enlarging diameter below such upper end, the main supply of. air to the carburetor being admitted to the lower part of such conical bore; there being also a metering pin mounted to rise and be set with the air valve, a liquid fuel supply container at a lower level, and an unobstructed passage thence to the metering pin permitting th-,\suction' in the mixing chamber to control freely the level and flow of liquid fuel to the metering pin.

14. In a carburetor of the metering pin type, a'caSing enclosing a mixing chamber in its upper portion and having air inlet provisions in its bottom part, a xed column rising from the bottom of said-teasing centrally therein having a cen-f tral air passage in its upper part and a lateral inlet to such passage at a lower level, a fuel supply .conduit extending upwardly, through said column within said central passage and located to permit flow of air between it and theboundof downwardly convergent taper carried by the air valve and extending downwardly into said said column, and the inner of these being.

a primary atomizing air current too small to operate the engine to which the carburetor is attached. y

l5. In a, carburetor of the metering pin type, the combination of a casing forming a mixing chamber and having a central column in its interior forming part ofthe fuel and air metering means, an air valve guided in said casing `to travel lengthwise of the column, having a, frusto-conical bore substantially fitting the extremity of said column only when the valve is inits lowermost positionand being of progressively enlarging diameter in the direction toward the base of the column, and a tapered fuel metering pin carried by the air valve in position to cooperate with the fuel supplying portion of said column; said conical bore being arranged'to control all of the air passing through the carburetor including that required to provide a combustible mixturel suitable for the idling speed of an internal combustion engine; a fuel supply tank at a lower level, and al floatless and unobstructed connection thence to the fuel supplying portion of said column.

16. A floatless carburetor having a mixing chamber in its interior and air inlet means at one end, air controlled means by which substantially all of the air supplied to the mixing chamber is controlled, comprising a valve member fitted to move in the casing, having a conical bore of convergent taper in the direction from the air inlet means toward the mixing chamber, and a 'stationary column extending from the air inlet end of the casing toward the mixing chamber within such bore, formed to obstruct suchr bore at its extremity only, and only when the air valve is in a position of near approach lto the'air inlet end of the casing; the relation of the'air valve to the column being that when the air valve is fully at the air inlet end of its travel the said column projects through and laps a little beyond the small end of the conical bore of the valve.

17. The combination with a constant-vacuum iloatless self feeding carburetor, of a fuel receptacle located at a level below that of the carburetor, a valveless vacuum fuel container located at a level intermediate those of the receptacle and carburetor, a fuel conduit leading from the receptacle to the container, and a separate conduit leading from the container to the carburetor; the container being thereby so arranged as to form a fuel trap to maintain a substantially constantl level of fuel in reference to the carburetor and prevent back flow of fuel from the carburetor to the-receptacle.

ROLLIN ABELL. 20 

